Human hair becomes soiled due to its contact with the surrounding atmosphere and, to a greater extent, from sebum secreted by the head. The build-up of the sebum causes the hair to have a dirty feel and an unattractive appearance. The soiling of the hair requires that it be shampooed frequently.
Shampooing the hair removes excess soil and sebum. However, the shampooing process has the disadvantage that the hair is left in a tangled and generally unmanageable state. A variety of approaches have been tried to alleviate this after-shampoo problem. These approaches range from the inclusion of hair conditioning aids in shampoos to post-shampoo application of hair conditioners, i.e., hair rinses. Difficulties associated with the use of conditioning aids in shampoos include compatibility problems and a greasy feel on the just-washed hair. Hair rinses typically work by depositing a polymeric film or other material onto the hair. However, the previous approaches to the after-shampoo problem have not been fully satisfactory. For one thing, hair rinses are generally liquid in nature and must be applied in a separate step following the shampooing, left on the hair for a length of time, and rinsed with fresh water. This process is time consuming and not convenient. The results obtained in this manner also have not been fully satisfactory due to the difficulties associated with the deposition and retention on the hair of the hair conditioning aid.
Conditioning and styling products ideally provide several benefits simultaneously. Desired benefits include conditioning, hold for styling, shine, etc. Existing conditioning and styling products are usually in the form of a spray, mousse, or gel. They usually contain a resin, such as an acrylate polymer or poly(vinylpyrrolidone/vinyl acetate) copolymer, which provides the hold, and other materials to modify the conditioning and other cosmetic benefits. They usually contain materials which plasticize the resin, reducing the flaking and making the hold less "crisp." When these products are applied to the hair, the volatile components such as water and alcohol evaporate, leaving the resin and other chemicals behind. If a plasticizer is used, it is usually at a very low level compared to the level of the resin. Too much plasticizer will significantly reduce the holding ability of the resin, make the product sticky, and create other undesirable aesthetic properties. Many different types of chemicals will plasticize a hair polymer, including glycerin, fragrances or other oils, silicones, and cosmetic esters.
A solid stick is used as the delivery form for many types of cosmetic products such as deodorants, lip conditioners, and color cosmetics. Stick formulas are generally based on either silicones, glycols and soap, or waxes. The glycol/soap base, which is water soluble or dispersible, is the traditional form for deodorants and antiperspirants. It consists primarily of water, glycols (such as glycerin or propylene glycol), alcohol and/or glycol esters, and is made into a solid form by addition of soap, usually sodium stearate.
The invention provides a cosmetic hair conditioning solid, especially in the form of a stick, that contains a hair styling polymer resin and results in a styling product that gives good hold to the hair, does not flake, and provides other cosmetic benefits, such as shine and conditioning. The bulk of the stick can be glycols, glycol esters, or other materials. In a traditional styling product, when glycols or glycol esters are present, their weight percent of the composition must be kept low to avoid plasticizing the resin to the point where it would lose most of its hold. However, in a solid of the invention the glycols or glycol esters are present at much higher weight percents of the composition and the composition has good hold. This difference in the effect of glycols and glycol esters in the properties of the compositions of the invention and their effect in traditional styling products emphasizes the different nature of the compositions of the invention.
The cosmetic hair conditioning solid of the present invention improves upon the prior art by providing a cosmetic hair conditioning composition that is in the form of a solid. The composition of the present invention is easy to use, both for conditioning and styling, and can be formed into any desired shape. The composition of the invention also requires a lesser amount of packaging than previous hair conditioners because it is more concentrated; the packaging constraints are also less stringent because it is a solid instead of a liquid or gel.